Collection was modified; enumeration operation may not execute while
adding control to a panel in update panel
Hi all I am having an update panel where I am having a Panel inside along
with some controls as follows
<asp:UpdatePanel ID="upPanel" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:Panel ID="Panel1" runat="server">
<asp:Label ID="Label1" runat="server" AssociatedControlID="txt1">
</asp:Label>
<asp:TextBox ID="txt1" runat="server"></asp:TextBox>
</asp:Panel>
</ContentTemplate>
For text box I am validation dynamically based on the database value for
that column is mandatory in page load as follows
RequiredFieldValidator rqrdColumn = new RequiredFieldValidator();
rqrdColumn.Display = ValidatorDisplay.None;
rqrdColumn.ID = "rqrd1";
rqrdColumn.ControlToValidate = txt1.ID;
rqrdColumn.ErrorMessage = "Can not be blank";
rqrdColumn.ValidationGroup = "vg";
ValidatorCalloutExtender vceColumn = new ValidatorCalloutExtender();
vceColumn.ID = "vce";
vceColumn.TargetControlID = rqrdColumn.ID;
panel.Controls.Add(rqrdColumn);
panel.Controls.Add(vceColumn);
updatepanel.ContentTemplateContainer.Controls.Add(panel);
updatepanel.Update();
Every thing works fine except that exception,
Collection was modified; enumeration operation may not execute
Can some one help me?
